Sim male fiancé refuses "try for baby"? Hates children. Is Pregnancy possible?

My brother created a female sim and sent her out to get pregnant with the first male sim she met. He didn't even look at the guy's traits. She got pregnant, so they got married. She had triplets. Only later did he learn that the guy had a "hates children" trait. Boy, that male sim must be bummed to be stuck with triplets.